<CascadingAuthenticationState>
  <Router AppAssembly="@typeof(Program).Assembly" PreferExactMatches="@true">
    <Found Context="routeData">
      <RouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)" />
    </Found>
    <NotFound>
      <LayoutView Layout="@typeof(MainLayout)">
        <p>Sorry, there's nothing at this address.</p>
      </LayoutView>
    </NotFound>
  </Router>
</CascadingAuthenticationState>

